The R.I. Building Code Commission and the R.I. Coastal Resources Management Council (CRMC) are in the final stages of drafting new rules that will require houses, roads and all other structures along the state’s 400 miles of coastline to be built higher.

The new regulations are a response to the coastal council’s forecast that climate change will cause the sea level to rise by 3 to 5 feet over the next 90 years – an assumption described as “relatively narrow and low” in the council’s policy book. A law passed last year directed the two agencies to develop the new rules, which officials hope to release for public comment late this fall or early winter.

“The goal is to take into account where water is going to be in the future, and even where it is now,” said Warren Ducharme, the building code commission’s staff architect.

In Providence, a 3-foot increase in sea level would leave the sidewalks in Waterplace Park underwater at high tide. The flood risk is so severe that the Federal Emergency Management Agency refers to the area around the bay in Providence as “the Achilles’ Heel of the Northeast.”

The new regulations will mandate that structures be built to withstand the “100-year flood” on top of the expected rise in sea level. The rules will cover building renovations or repairs that equal or exceed 50 percent of a structure’s value, as well as new construction, said Grover Fugate, executive director of the CRMC.

There also will be different rules for various types of structures. For example, there will be more conservative standards for bridges, which are expected to last for decades, or hospitals, which are vital in a public emergency.

“It’s not one size fits all,” said Pam Rubinoff, senior coastal manager for the Coastal Resources Center at the University of Rhode Island. The new rules will ensure the state’s structures can withstand major storms and ecological changes, she said.

“This is about public safety, and public and private investment,” Rubinoff added.

The real estate and construction sectors are nervously awaiting the proposed rules. Industry leaders said they are concerned about the impact additional regulation would have on the coast.

“The devil’s in the details,” said Roger Warren, executive director of the Rhode Island Builders Association, including the impacts on buildable land, property prices and existing homes. “We know it will have an impact, and we know we’ll have concerns about those impacts. We’re just trying to determine what those would be.”

A spokeswoman for the Rhode Island Association of Realtors said the new regulations are on the watch list of the group’s government affairs committee.

However, Rubinoff and others involved in crafting the rules say they are looking out for property owners’ investments by making sure rules reflect current science. “You want to be sure the information is correct and that the design is correct, and what we’re finding with sea level rise is that the assumptions have changed a bit,” she said.

Ducharme, the building commission architect, said that new structures in southern states that have been built with updated codes have survived major storms, including Hurricane Katrina. “So the new codes work,” he said.

“Hopefully, this will set defendable, survivable guidelines for your property.”

Fugate also said the stricter standards will lower property-insurance rates “quite substantially.”

John King, a professor at URI’s Graduate School of Oceanography, said it makes sense for the two agencies to plan for a 3- to 5-foot sea level rise, which he said reflects his best estimate. •